Lagging chromosomes in KIF18A KO cells are located near the spindle poles in late anaphase. (A) Representative images of late anaphase RPE1 cells that were fixed and labeled with antibodies against centromeres and spindle poles. Arrowheads indicate lagging chromosomes. (B) Left: Schematic depicting how lagging chromosome positions were measured and normalized within each half-spindle. Right: Plot showing normalized lagging chromosome-to-pole distances measured in KIF18A KO RPE1 cells and nocodazole washout–treated RPE1 WT cells. n = 47 (RPE1 WT + nocodazole), n = 27 (KIF18A KO). Data collected from three independent experiments. *, P < 0.01. Data points indicate individual lagging chromosomes. Error bars represent SD. (C) Left: Schematic depicting how lagging chromosome angles were measured relative to the central spindle axis. Measured angles were converted to equivalent angles within the range of 0° and 90°. Right: Plot of lagging chromosome angles relative to the central spindle axis for the indicated conditions. n = 29 (KIF18A KO), n = 47 (RPE1 nocodazole washout). P = 0.19, ns. Data collected from three independent experiments. Data points indicate individual lagging chromosomes. Statistical comparisons were made using a two-tailed unpaired Student’s t test. Avg, average; Noc., nocodazole.